Incidence of asymptomatic deep vein thrombosis in patients with tunneled dialysis catheters undergoing routine venous mapping.

Abstract Background: Tunneled dialysis catheters (TDCs) are widely used for hemodialysis access but are associated with various complications, including central venous stenosis and thrombosis. While symptomatic thrombotic events are well documented, the incidence and clinical correlates of asymptomatic deep vein thrombosis (DVT) detected during routine venous mapping remain unclear. This study investigates the frequency and characteristics of incidental DVT in patients with TDCs undergoing venous mapping study at the University of Oklahoma Health Sciences Center. Methods: We retrospectively reviewed 124 adult patients with TDCs who underwent routine venous mapping at our tertiary care center between July 1st, 2023, and December 31st, 2024. DVTs were identified through radiographic reports. Superficial venous thromboses were analyzed separately. Demographics, comorbidities, laboratory values, and catheter-related variables were compared between patients with and without DVT using Mann-Whitney U and Fisher's exact tests. Results: Among 124 patients with TDCs, 6 (4.8%) had incidentally detected DVTs and 2 (1.6%) had superficial thrombosis. Patients who developed DVT were younger, with a median age of 49 years compared to 63 years in those without DVT and had a lower median BMI (25.8 vs 29.8). The median hemoglobin level at the time of venous mapping was significantly lower in the DVT group (8.1 g/dL) compared to the non-DVT group (10.3 g/dL; p=0.032). Median white blood cell count (5.6 vs 7.42 ×10⁹/L) and platelet count (145 vs 208 ×10⁹/L) did not differ significantly between the DVT and non-DVT groups. Comorbid conditions such as hypertension (67% in DVT vs 86% in non-DVT) and diabetes (33% in DVT vs 57% in non-DVT) were more prevalent among patients without DVT. One DVT-positive patient had active malignancy, and another had a history of line-associated DVT. None of the DVT patients had first-time dialysis access, compared to 26 patients in the DVT-negative group. No consistent differences were found based on the location of the vein accessed or the tip location. All DVTs were asymptomatic and detected incidentally during the venous mapping study. Conclusions: In this cohort of TDC-dependent hemodialysis patients, 4.8% had asymptomatic, incidentally detected DVTs despite the absence of clinical signs or symptoms. Lower hemoglobin at the time of mapping was significantly associated with DVT. These findings underscore the potential value of routine vascular imaging for uncovering subclinical thrombotic events in at-risk patients and suggest a need for prospective studies evaluating the role of prophylactic anticoagulation in patients with TDCs.